Covert Attack in Load Frequency Control of Power Systems

The purpose of this work is to design a covert agent structure that can create a non-zero frequency deviation in the load frequency control (LFC) system and illustrate the necessity of a secure communication network for the load frequency control. LFC systems are one of the most time-consuming control loops of power systems that are vulnerable to cyber-attacks and disturbances. Cyber-attacks like covert attacks can affect the frequency performance of the LFC system without being detected, as the covert adversaries cancel out the influence of the deceptively added actuation signal by deducting the corresponding effect from the measurement signal. In this paper, a covert agent with feedback structure is formulated and it is shown that the covert adversary can take control of LFC system through the covert reference signal and can keep the relative offset between actual frequency deviation of LFC system and the measurement signal received by the integral controller within safe limits, such that the attacker remains undetected.